1. Field of the Invention
The invention relates to a manufacturing device and a manufacturing method for a synthetic resin hollow molded body. More particularly, the invention relates to a manufacturing device and a manufacturing method for efficiently manufacturing a synthetic resin hollow molded body including three members, which are a first split assembly member, a second split assembly member and a third split assembly member. The invention is widely applied to manufacture of an intake manifold and the like of an internal combustion engine, and to a field related thereto.
2. Description of the Related Art
As a synthetic resin hollow molded body, there is a complex-shaped product, such as an intake manifold for an automobile, which includes a plurality of nonlinear pipes. As shown in FIG. 10, an intake manifold 30 includes a first split assembly member 31, a second split assembly member 32, which make a pair, and a box-shaped third split assembly member 33 which is provided on an end portion of the second split assembly member 32. As a manufacturing method for the intake manifold, a method including an injection molding process and a vibration welding process is known. In the injection molding process, contact portions of the first split assembly member and second split assembly member that are molded by a first injection are jointed by a second injection. In the vibration welding process, the contact portion of the jointed second split assembly member and the contact portion of the third split assembly member are jointed by the vibration welding or the like. As a conventional injection molding device used in the aforementioned injection molding process, for example, an injection molding devices disclosed in Japanese Patent-Laid Open Publication No. 4-331123 and Japanese Patent Laid-Open Publication No. 6-297501 are known. Japanese Patent Laid-Open Publication No. 4-331123 discloses the injection molding device including a sliding mechanism which relatively slides the first split assembly member and second split assembly member so as to make them face each other in a die opening/closing direction, such that the contact portions of the first split assembly member and the second split assembly member, which are molded by the first injection, contact each other. Japanese Patent Laid-Open Publication No. 6-297501 discloses the injection molding device including a rotating mechanism which relatively rotates the first split assembly member and the second split assembly member so as to make them face each other in the die opening/closing direction.
In the aforementioned conventional manufacturing method for an intake manifold, the intake manifold is manufactured through the injection molding process and the vibration welding process. Accordingly, it is necessary to control the two different manufacturing processes, which reduces manufacturing efficiency. In addition, as manufacturing equipment, both an injection molding device used in the injection molding process and a vibration welding device used in the vibration welding process are required, which increases a cost of equipment. Further, generally, only a molded product having a relatively simple shape can be molded by the vibration welding, and a flash receiver needs to be provided, which reduces flexibility in designing a molded product. Therefore, in order to solve the aforementioned problems, a method can be suggested in which the vibration welding process is not performed and the intake manifold is manufactured only by the injection molding process, that is, a method for manufacturing the intake manifold including the first split assembly member, second split assembly member, and the third split assembly member using the conventional injection molding device. However, in the conventional injection molding device, the sliding mechanism (or the rotating mechanism) is appropriate for relatively moving the two members, which are the first split assembly member and the second split assembly members. Accordingly, even when two sliding mechanisms (or the two rotating mechanisms) are simply provided, or both the sliding mechanism and the rotating mechanism are simply provided, it is impossible to appropriately move the three members, which are the first split assembly member, second split assembly member, and the third split assembly member, so as to make them face one another in the die opening/closing direction. Further, for example, when two sliding mechanisms are simply provided, driving means such as a hydraulic cylinder which forms the sliding mechanism protrudes in a direction in which the sliding mechanism slides, which results in upsizing of the entire device. When two rotating mechanisms are simply provided, the entire device is also upsized so as to obtain a rotation area for the rotating mechanisms.